Is not the tracking code on the receipt? They can just plug in the number and find out the info of where it is going.
I usually see my food bank location on the comments as well.
The surcharge for C is based on the following:
re priority:
"Parcels addressed for delivery to zones 1-4 (including local)
that weigh less than 20 pounds but measure more than 84
inches in combined length and girth (but not more than 108
inches) are charged for a 20-pound parcel (balloon price)
based on the applicable zone.
3. Parcels addressed for delivery to zones 5-9 that exceed one
cubic foot (1,728 cubic inches) are charged based on the
actual weight or the dimensional weight, whichever is greater."